This invention relates to an article having a cylindrical portion fitted with a cap member, and more particularly to means for detachably fastening the cap member to the cylindrical portion of the article. A typical embodiment of the invention is a capped governor case in an automatic transmission for automobiles.
There are various articles having a generally cylindrical portion covered with a detachably fastened cap member. In automobile industries, a typical example of such articles is a capped governor case in which is encased a governor valve, or governor valves, to produce a governor pressure as a control hydraulic pressure in an automatic transmission.
According to a typical conventional method of detachably fastening a cap member to, for example, an automatic transmission governor case, an external screw thread is cut on the cylindrical portion of the governor case and an internal screw thread is cut in the cap member, so that the cap is fastened by turning it on the governor case. Another conventional capping method is the use of bolts. In this case, an article such as a governor case to be capped is made to have a flange around the cylindrical portion and several tapped holes are formed in the flange in a circumferential arrangement, whereas a cap member is formed with bolt holes in compliance with the tapped holes in the flange of the case.
From an industrial viewpoint, a disadvantage common to these conventional capping methods is the necessity for time-consuming machining processes to cut the screw threads. Furthermore, fastening of caps by either of these methods requires increased time and labor costs. Besides, unfastening of the fastened cap according to the need cannot be accomplished quickly.